Dual chamber syringe with retractable needle

ABSTRACT

Embodiments of a retractable syringe assembly are provided that include a dual syringe barrel configuration. One or more embodiments include reuse prevention features and features that prevent premature activation of the retraction mechanism. Methods for aspirating and expelling liquid from medical devices are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 61/366,874, filed Jul. 22, 2010, thedisclosures of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

Aspects of the present invention relate to syringe assemblies thatinclude a retractable needle and reuse prevention features and methodsof using such syringe assemblies.

BACKGROUND

Needle retraction features have been incorporated into syringeassemblies to protect users from needle stick injuries. In conventionalassemblies, the needle hub assemblies, including a needle cannula, areattached to the syringe barrel and must be withdrawn into the syringebarrel by a user or by a retraction feature. Alternatively, a needleshield may be placed over the needle cannula by the user or otherwise.

In conventional syringe assemblies in which the needle hub assembliesare retracted into the syringe barrel by a retraction feature, theretraction feature is often provided within the syringe barrel and/orthe plunger rod disposed within the syringe barrel. Specifically, theplunger rod may include a chamber that houses the needle hub after it isretracted. The retraction feature typically includes a cutting elementdisposed between the plunger rod and the stopper that is used to openthe stopper after the contents of the syringe barrel are expelled, toexpose the chamber of the plunger rod to receive the retracted needlehub. A spring is often incorporated in the needle hub assemblies todrive the retraction of the needle hub into the plunger rod.

Accordingly, such retraction features require cutting, breaking,piercing or other force-intensive mechanical action for activation and,thus, increased complexity to enable the sealed plunger and stopper tobe breached during activation. Further, as most conventionally designedretractable needles are activated after dosing by continued pressure onthe rear of the plunger rod, inadvertent activation of the retractionfeature may occur since the same forces must be applied when expellingthe contents of the syringe barrel. Moreover, some devices may beinadvertently activated during dosing if sufficient pressure isgenerated during expulsion of the contents of the syringe, for example,when the medication is viscous and requires the user to apply additionalpressure or force to the plunger rod, which exceeds the force requiredto activate the retraction feature. Premature activation is especiallyproblematic in applications where high forces are applied to the plungerrod, for example, during high speed injections.

The retraction features of conventional syringe barrels that areplunger-activated must withstand increased syringe pressures andassociated increase in force applied to the plunger rod, as describedabove. These increased forces and pressure lead to a requirement forlarge activation forces which could exceed the operational forces inorder to prevent premature activation. Since most conventional syringebarrels employ an additional plunger motion after full dispensing, andin the same manner as the dispensing motion, a threshold force must beused to allow the user to differentiate between a fully bottomed plungerand the activation of the retraction feature. The threshold force may bedifficult to ascertain and maintain separately from the force applied tothe plunger rod to expel the contents of the syringe barrel. Further,proper application of the threshold force may require a user to positionthe syringe barrel and the needle cannula at an increased angle to thepatient's skin, instead of positioning the syringe barrel and needlecannula substantially parallel to the patient's skin. The additionalforce required to activate the retraction feature may cause additionalpressure to be generated at the stopper or other removable opening inthe plunger rod, which may be sufficient to cause the stopper and/orplunger rod to malfunction.

In conventional retractable syringe assemblies where the retractionfeature and the subsequent housing of the needle hub are containedwithin the fluid path, the retraction feature and housing may cause avolume of medication to become trapped within the syringe barrel,thereby increasing waste and potentially affecting dosing accuracy.Further, a portion of the trapped medication may be expelled during theactivation of the retraction feature causing splatter, if the retractionfeature is activated when the needle cannula is outside of the patient,or an unintended increase in the dose administered to the patient, ifthe retraction feature is activated when the needle cannula is in thepatient. Placement of the retraction feature within the syringe barrelmay also cause trapped air to remain in the syringe barrel when purgingor priming the syringe. This can lead to the possibility of injectedair. The size of the syringe barrel must also accommodate the retractionfeature and the needle hub assembly that will be housed therein afterretraction.

In syringe assemblies which do not house the retraction feature withinthe fluid path, the retraction feature is often disposed at a locationthat requires the user to change their grip of the syringe assembly toactivate the retraction feature. Such designs may not be ergonomicallyacceptable to certain users of these syringe assemblies.

Conventional retraction syringe assemblies often do not incorporatereuse prevention features, and thus, the retraction mechanism may bereset so the syringe barrel may be reused. The reuse of syringeassemblies without sterilization or sufficient sterilization is believedto facilitate the transfer of contagious diseases.

Accordingly, it would be desirable to provide a retractable syringeassembly with a retraction feature that does not interfere with normaloperation of the syringe assembly and reduces the risk of prematureactivation or the retraction mechanism. It would also be desirable toprovide a retractable syringe assembly which incorporates a reuseprevention feature.

SUMMARY OF THE INVENTION

One aspect of the present invention pertains to a syringe assemblycomprising a fluid barrel including a sidewall having an inside surfacedefining a fluid chamber for retaining fluid and having a firstcross-sectional width, an open proximal end and a distal end including adistal wall; a plunger rod disposed within the fluid chamber comprisinga distal end, a proximal end, a plunger rod body extending from thedistal end to the proximal end, and a stopper disposed at the distal endof the plunger rod for forming a fluid-tight seal with the insidesurface of the barrel; a retraction barrel disposed adjacent to thesidewall of the fluid barrel, the retraction barrel including a wallhaving an interior surface defining a needle chamber, an open proximalend, an open distal end including a barrier wall, an aperture betweenthe wall of the retraction barrel and the sidewall of the fluid barrelpermitting fluid communication between the fluid chamber and the needlechamber and a needle hub assembly comprising a needle hub, a needlecannula attached to the needle hub, the needle cannula being in fluidcommunication with the aperture and biased to move in a proximaldirection; and a trigger element disposed within the needle chamber andmoveable within the retraction barrel independently from the plungerrod, the trigger element providing a trigger force causing the needlecannula to retract into the retraction barrel.

In one or more embodiments of the present invention, the needle hubassembly is disposed at the open distal end of the retraction barrel,the needle hub assembly further comprising a first attachment portion,the trigger element including a second attachment portion for engagingthe first attachment portion. In one or more embodiments of the presentinvention, the trigger force disengages the second attachment portionfrom the first attachment portion so the needle cannula is retractedwithin the retraction barrel. In one or more embodiments of the presentinvention, the needle cannula is biased by a spring disposed between theneedle hub and the retraction barrel that exerts a force on the needlecannula in a proximal direction. In one or more embodiments of thepresent invention, the retraction barrel includes a tapered distal endand the spring is disposed between the needle hub and the tapered distalend of the retraction barrel.

In one or more embodiments of the present invention, the firstattachment portion comprises a groove disposed on at least a portion ofan outside surface of the needle hub and the second attachment elementcomprises at least one flexible arm extending distally from the distalend of the trigger element, the flexible arm including at least onelocking member that extends inwardly for engaging the groove disposed onthe needle hub. In one or more embodiments of the present invention, thetrigger element includes a free proximal end, a free and open distal endthat provides the trigger force, and a trigger element body extendingfrom the proximal end to the distal end and including an interiorsurface defining a hollow interior. In one or more embodiments of thepresent invention, the needle cannula is retracted into the retractionbarrel and housed within the hollow interior of the trigger element. Inone or more embodiments of the present invention, wall of the retractionbarrel includes a release opening and the trigger element body includesa release detent disposed adjacent to distal end of the trigger elementthat engages the opening of the retraction barrel. In one or moreembodiments of the present invention, the trigger force includesapplication of a force on the trigger element in the distal directionthat is sufficient to disengage the release detent of the triggerelement from the release opening in the wall of the retraction barrel.In one or more embodiments of the present invention, the retractionbarrel includes a rib that extends proximally from the barrier wall forretaining the flexible arm upon application of the trigger force. In oneor more embodiments of the present invention, upon application of thetrigger force, the flexible arm is moved in a proximal direction todisengage the locking member from the groove of the needle hub andslides over the rib to permit the needle cannula to retract into theretraction barrel.

In one or more embodiments of the present invention, the needle hubassembly is removably attached to the retraction barrel. In one or moreembodiments of the present invention, the needle hub assembly ispermanently attached to the retraction barrel. In one or moreembodiments of the present invention, the trigger force is at least 4lbf.

In one or more embodiments of the present invention, prior to theapplication of the trigger force, the proximal end of the triggerelement is aligned with the proximal end of the plunger rod. In one ormore embodiments of the present invention, after the application of thetrigger force, the proximal end of the trigger element is no longeraligned with the proximal end of the plunger rod. In one or moreembodiments of the present invention, the alignment of the triggerelement and the plunger rod provides visual indication of the retractionof the needle cannula.

In one or more embodiments of the present invention, the inside surfaceof the fluid chamber sidewall includes a retaining ring adjacent to theproximal end defining a second cross-sectional width that is less thanthe first cross-sectional width and the plunger rod body includes aflexible protrusion having a cross-sectional width greater than thecross-sectional width of the barrel at the rib and a frangible portion.In one or more embodiments of the present invention, the contact betweenthe stopper and the distal wall of the barrel causes the protrusion toadvance distally past the rib in the barrel and lock the plunger rod inthe barrel to prevent reuse of the syringe assembly. In one or moreembodiments of the present invention, the distal end of the plunger rodincludes a stopper-engaging portion and the stopper is attached to thestopper-engaging portion of the plunger rod, the stopper being distallyand proximally movable relative to the stopper-engaging portion for apre-selected axial distance such that when a force is applied to theplunger rod in the distal direction and the distal end of the stopper isin contact with the distal wall of the barrel, the protrusion ispermitted to advance distally past the rib in the barrel and lock theplunger rod in the barrel to prevent reuse of the syringe assembly. Inone or more embodiments of the present invention, continuous applicationof a force on the plunger rod in the proximal direction after theprotrusion has advanced distally past the rib causes the frangibleportion to break. In one or more embodiments of the present invention,continuous application of a force on the plunger rod in the proximaldirection after the protrusion has advanced distally past the rib causesthe frangible portion to break.

Another aspect of the present invention pertains to a syringe assemblycomprising a fluid barrel including a sidewall having an inside surfacedefining a fluid chamber for retaining fluid and having a firstcross-sectional width, an open proximal end and a distal end including adistal wall; a plunger rod disposed within the fluid chamber comprisinga distal end, a proximal end, a plunger rod body extending from thedistal end to the proximal end, and a stopper disposed at the distal endof the plunger rod for forming a fluid-tight seal with the insidesurface of the barrel; a retraction barrel disposed adjacent to thesidewall of the fluid barrel, the retraction barrel including a wallhaving an interior surface defining a needle chamber, an open proximalend, an open distal end including a barrier wall, an aperture betweenthe wall of the retraction barrel and the sidewall of the fluid barrelpermitting fluid communication between the fluid chamber and the needlechamber and a needle hub assembly comprising a needle hub, a needlecannula attached to the needle hub, the needle cannula being in fluidcommunication with the aperture and biased to move in a proximaldirection; and a trigger element disposed adjacent the distal end of thefluid barrel to provide a trigger force causing the needle cannula toretract into the retraction barrel.

Yet another aspect of the present invention pertains to a syringeassembly comprising a barrel comprising including an open proximal end,sidewall having an inside surface defining a fluid chamber for retainingfluid and having a first cross-sectional width and a needle chamber forhousing a needle hub assembly, the fluid chamber and the needle chamberbeing circumscribed by a common wall and divided into separate chambersin fluid communication; a needle hub assembly disposed within the needlechamber, the needle hub assembly comprising a needle hub, a needlecannula supported within the needle hub, the needle cannula in fluidcommunication with the first aperture and biased to move in a proximaldirection; a plunger rod disposed within the fluid chamber comprising adistal end, a proximal end, a stopper disposed at the distal end of theplunger rod for forming a fluid-tight seal with the inside surface ofthe barrel and a plunger rod body extending from the distal end to theproximal end; and a retraction member disposed within the needlechamber, the retraction member including a proximal end and an opendistal end to cause the needle cannula to retract and be retractedwithin the retraction member.

Another aspect of the present invention pertains to a syringe assemblycomprising a barrel comprising including an open proximal end, sidewallhaving an inside surface defining a fluid chamber for retaining fluidand having a first cross-sectional width and a needle chamber forhousing a needle hub assembly, the fluid chamber and the needle chamberbeing circumscribed by a common wall and divided into separate chambersin fluid communication; a needle hub assembly disposed within the needlechamber, the needle hub assembly comprising a needle hub, a needlecannula, the needle cannula in fluid communication with the firstaperture and biased to move in a proximal direction; a plunger roddisposed within the fluid chamber comprising a distal end, a proximalend, a stopper disposed at the distal end of the plunger rod for forminga fluid-tight seal with the inside surface of the barrel and a plungerrod body extending from the distal end to the proximal end; and atrigger element adjacent the distal end of the plunger rod to provide aforce to cause the needle cannula to retract and be retracted within theneedle chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view a retractable syringe assemblyaccording to one or more embodiments of the present invention;

FIG. 2 illustrates a side view of the syringe assembly shown in FIG. 1;

FIG. 3 illustrates a view of the syringe assembly shown in FIG. 1 fromthe proximal end of the syringe assembly;

FIG. 4 illustrates a side cross-sectional view of the syringe assemblyshown in FIG. 1, wherein the retraction barrel is located outside of thefluid barrel;

FIG. 5 illustrates a cross-sectional view of the fluid barrel and theretraction barrel taken along lines 5-5, with the trigger element andplunger rod removed from the assembly;

FIG. 6 illustrates a side cross-sectional view of the syringe assemblyaccording to one or more embodiments, wherein the retraction barrel isnested within the fluid barrel;

FIG. 7 illustrates a cross-sectional view of the fluid barrel and theretraction barrel taken along lines 7-7;

FIG. 8 illustrates a partial perspective view of the plunger rod, needlehub assembly and trigger element of FIGS. 4 and 6 prior to retraction ofthe needle hub assembly;

FIG. 9 illustrates a partial perspective view of the plunger rod, needlehub assembly and the trigger element shown in FIG. 8 after applicationof a force on the trigger element in the distal direction;

FIG. 10 illustrates a partial perspective view of the plunger rod,needle hub assembly and the trigger element shown in FIG. 9, after thetrigger element breaks the frangible element;

FIG. 11 illustrates a partial perspective view of the plunger rod,needle hub assembly and the trigger element shown in FIG. 10 after aportion of the needle hub assembly begins to retract into the retractionbarrel;

FIG. 12 illustrates a partial perspective view of the plunger rod,needle hub assembly and the trigger element shown in FIG. 11 after theportion of the needle hub assembly is more fully retracted into theretraction barrel;

FIG. 13 illustrates a perspective view of the assembly of a needle hubassembly according to according to one or more embodiments;

FIG. 14 illustrates the needle hub assembly of FIG. 13 as the needlecannula and needle cannula support is being inserted into the needlehub;

FIG. 15 illustrates the needle hub assembly of claim 14 as the needlehub is being formed around the needle cannula and the needle cannulasupport;

FIG. 16 illustrates the needle hub assembly of claim 15 as needle hub ismore fully being formed around the needle cannula and the needle cannulasupport;

FIG. 17 the assembled needle hub assembly of claim 16;

FIG. 18 illustrates a perspective view of a needle hub assembly beingassembled to a retraction barrel according to one or more embodiments;

FIG. 19 illustrates the needle hub assembly shown in FIG. 18 attached toa needle shield as it is placed on the retraction barrel also shown inFIG. 18;

FIG. 20 illustrates the needle hub assembly and needle shield shown inFIG. 19 after the needle shield engages the needle hub assembly;

FIG. 21 illustrates the needle hub assembly and needle shield shown inFIG. 20 after rotation with respect to the retraction barrel;

FIG. 22 illustrates the needle hub assembly and needle shield shown inFIG. 21 after alignment of the open conduit of the needle hub assemblyand the aperture of the retraction barrel;

FIG. 23 illustrates the needle hub assembly and needle shield shown inFIG. 22 after removal of the needle shield;

FIG. 24 illustrates cross-sectional side view of a retractable syringeassembly according to one or more embodiments;

FIG. 25 illustrates an enlarged partial cross-sectional view of theretractable syringe assembly shown in FIG. 24;

FIG. 26 illustrates an enlarged partial cross-sectional view of theretractable syringe assembly shown in FIG. 25 after application of thetrigger force on the needle hub assembly;

FIG. 27A illustrates a cross-sectional top view of the dual chambersyringe barrel shown in FIG. 24;

FIG. 27B illustrates a cross-sectional side view of the dual chambersyringe barrel shown in FIG. 27A;

FIG. 27C illustrates a cross-sectional view of the dual chamber syringebarrel shown in FIG. 27A taken from the proximal end;

FIG. 27D illustrates a cross-sectional side view of the dual chambersyringe barrel shown in FIG. 27A taken from the distal end;

FIG. 28 illustrates a side view of the needle hub assembly shown in FIG.24;

FIG. 28A illustrates a cross-sectional view of the needle hub assemblyshown in FIG. 28 taken along line A-A;

FIG. 29 illustrates a partial, cross-sectional view of a retractablesyringe assembly showing the proximal end according to one or moreembodiments;

FIG. 30 illustrates the proximal end of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 31 illustrates the proximal end of a retractable syringe assemblyshown in FIG. 30 after application of a force on the plunger rod in thedistal direction;

FIG. 32 illustrates the proximal end of a retractable syringe assemblyshown in FIG. 31 the trigger element locked within the retraction barrelafter application of a force on the trigger element in the distaldirection;

FIG. 33 illustrates a partial perspective view of a plunger rod, triggerelement and needle hub assembly according to one or more embodiments;

FIG. 34 illustrates a partial perspective view of a plunger rod, triggerelement and needle hub assembly shown in FIG. 33 after application of aforce on the trigger element in the distal direction;

FIG. 35 illustrate a partial perspective view of a plunger rod, triggerelement and needle hub assembly shown in FIG. 34 during application of aforce on the trigger element in the distal direction, as the triggerelement contacts the needle hub assembly;

FIG. 36 illustrates a partial perspective view of a plunger rod, triggerelement and needle hub assembly shown in FIG. 35 after the triggerelement contacts the needle hub assembly, as the trigger element exertsa trigger force on the needle hub assembly;

FIG. 37 illustrates a partial perspective view of a plunger rod, triggerelement and needle hub assembly shown in FIG. 36 after a portion of theneedle hub assembly is retracted into trigger element;

FIG. 38 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 38A illustrates a side view of the retractable syringe assemblyshown in FIG. 38;

FIG. 38B illustrates a view of the retractable syringe assembly shown inFIG. 38 taken from the proximal end;

FIG. 39 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 39A illustrates a side view of the retractable syringe assemblyshown in FIG. 39;

FIG. 39B illustrates a view of the retractable syringe assembly shown inFIG. 39 taken from the proximal end;

FIG. 40 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 41 illustrates a side view of the retractable syringe assemblyshown in FIG. 40;

FIG. 42 illustrates a view of the retractable syringe assembly shown inFIG. 40 taken from the proximal end;

FIG. 43 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 43A illustrates a side view of the retractable syringe assemblyshown in FIG. 43;

FIG. 43B illustrates a view of the retractable syringe assembly shown inFIG. 43 taken from the proximal end;

FIG. 44 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 44A illustrates a side view of the retractable syringe assemblyshown in FIG. 44;

FIG. 44B illustrates a view of the retractable syringe assembly shown inFIG. 44 taken from the proximal end;

FIG. 45 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 46 illustrates a side view of the retractable syringe assemblyshown in FIG. 45;

FIG. 47 illustrates a view of the retractable syringe assembly shown inFIG. 45 taken from the proximal end;

FIG. 48 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 49 illustrates a side view of the retractable syringe assemblyshown in FIG. 48;

FIG. 50 illustrates a view of the retractable syringe assembly shown inFIG. 48 taken from the proximal end;

FIG. 51 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 52 illustrates a side view of the retractable syringe assemblyshown in FIG. 51;

FIG. 53 illustrates a view of the retractable syringe assembly shown inFIG. 52 taken from the proximal end;

FIG. 54 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 54A illustrates a side view of the retractable syringe assemblyshown in FIG. 54;

FIG. 54B illustrates a view of the retractable syringe assembly shown inFIG. 54 taken from the proximal end;

FIG. 55 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 56 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 56A illustrates a side view of the retractable syringe assemblyshown in FIG. 56;

FIG. 56B illustrates a view of the retractable syringe assembly shown inFIG. 56 taken from the proximal end;

FIG. 57 illustrates a perspective view of a retractable syringe assemblyaccording to one or more embodiments;

FIG. 57A illustrates a side view of the retractable syringe assemblyshown in FIG. 57;

FIG. 57B illustrates a view of the retractable syringe assembly shown inFIG. 57 taken from the proximal end;

FIG. 58 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments;

FIG. 59 illustrates a perspective view of the proximal end of aretractable syringe assembly shown in FIG. 58 after rotation of thetrigger element to prevent movement of the trigger element in the distaldirection;

FIG. 60 illustrates a perspective view of the proximal end of aretractable syringe assembly shown in FIG. 59 after rotation of thetrigger element to permit movement of the trigger element in the distaldirection;

FIG. 61 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments;

FIG. 62 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments;

FIG. 63 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments;

FIG. 64 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments;

FIG. 65 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments; and

FIG. 66 illustrates a perspective view of the proximal end of aretractable syringe assembly according to one or more embodiments.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the invention, it isto be understood that the invention is not limited to the details ofconstruction or process steps set forth in the following description.The invention is capable of other embodiments and of being practiced orbeing carried out in various ways.

In this disclosure, a convention is followed wherein the distal end ofthe device is the end closest to a patient and the proximal end of thedevice is the end away from the patient and closest to a practitioner.

Aspects of the invention pertain to retractable syringe assemblies andmethods of aspirating and expelling a liquid from a syringe assembly.

A first aspect of the present invention pertains to a retractablesyringe assembly having a retraction feature that is activated by theuser to retract a needle hub assembly, which includes a needle cannula,into the syringe assembly.

In the embodiment shown in FIGS. 1-5, the retractable syringe assemblyincludes a dual syringe barrel 101 that includes fluid barrel 110 and aretraction member or retraction barrel 120. The retractable syringe alsoincludes a needle hub assembly 140, a plunger rod 160, stopper 170 and atrigger element 190. The fluid barrel shown in FIG. 4, includes a distalend 111, a open proximal end 119, a sidewall 112 extending from thedistal end 111 and the proximal end 119 including an inside surface 114defining a chamber 115. The inside surface 114 defines a cross-sectionalwidth and may include a reuse prevention feature, that will be discussedin greater detail below. The distal end 111 includes a distal wall 117that encloses the distal end 111. In the embodiment shown, the sidewall112 includes a first aperture 123 for permitting fluid communicationbetween the fluid barrel and the retraction barrel. As will be discussedin greater detail below, the first aperture 123 also permits fluidcommunication between a needle cannula disposed within the retractionbarrel 120 and the retraction barrel 120 and the fluid barrel 110.

The fluid barrels shown in FIGS. 1-7 may include a reuse preventionfeature. Specifically, the fluid barrel 110 may include a retainingelement 109 that extends around the entire circumference of the insidesurface 114 of the fluid barrel 110 at a location adjacent to theproximal end 119 of the fluid barrel. The cross-sectional width of theinside surface 114 at the retaining element is less than the firstcross-sectional width or the cross-sectional width of the inside surface114 at the remaining locations along the length of the fluid barrel. Inone or more embodiments, optional tabs or detents can be used to createa region of the fluid barrel 110 having a cross-sectional width that isless than the first cross-sectional width of the fluid barrel 110. Theretaining element may also be shaped to facilitate activation of thereuse prevention feature. For example, the fluid barrel 110 may alsoinclude a diameter transition region disposed proximally adjacent to theretaining element at the proximal end 119 of the fluid barrel 110. Thecross-sectional width of the inside surface 114 of the fluid barrel atthe diameter transition region increases from the distal end 111 to theproximal end 119 of the fluid barrel 110. As will be described ingreater detail below, in embodiments of the retractable syringe assemblythat utilize a reuse prevention feature, the reuse prevention feature ofthe fluid barrel 110 cooperates with corresponding reuse preventionfeatures on plunger rod 160 to lock the plunger rod 160 within the fluidbarrel 110 and/or to disable the plunger rod 160 from further use.

An alternative embodiment is shown in FIGS. 6-7, wherein the retractablesyringe assembly may include a single barrel 200. In such embodiments, aportion of the barrel is divided by a common wall or dividing wall 201into a fluid barrel 210 and the remaining portion of the barrel housesthe retraction feature and the needle hub assembly and is referred to asthe retraction barrel 220. The dividing wall 201 may include an aperture232 for permitting fluid communication between the fluid barrel 210 andthe retraction barrel 220. The single barrel 200 of FIGS. 6-7 providesan ergonomic design which improves grip by providing a large diameterfor small syringe sizes.

In the embodiments shown in FIGS. 1-5, the retraction barrel 120 isdisposed adjacent to the sidewall 112 of the fluid barrel 110 in theembodiment shown in FIG. 4. The retraction barrel 120 is configured tohouse a needle hub assembly 140 therein and the retraction feature. Theretraction barrel 120 includes an open distal end 121 and an openproximal end 129. A wall 122 having an interior surface 124 defining theneedle chamber 125 extends from the distal end 121 to an open proximalend 129. The wall 122 of the retraction chamber is adjacent to thesidewall 112 of the fluid barrel 110. In one or more embodiments, thewall 122 may extend around the portions of the retraction barrel 120that are not in direct contact with fluid barrel 110 and the sidewall112 may form the barrier between the retraction barrel 120 and the fluidbarrel 110. In other words, the outside surface of the sidewall 112 mayform the interior surface 114 of the retraction barrel 120 along theportion of the retraction barrel 120 that is in direct contact with thefluid barrel 110.

The size of the needle chamber 125 may be modified to accommodate theneedle hub assembly 140 and/or the retraction feature. According to oneor more embodiments, the interior surface 124 of the retraction barrel120 has a cross-sectional width that is smaller than the firstcross-sectional width of the fluid barrel 110. In specific embodiments,the cross-sectional width of the interior surface 124 of the retractionbarrel is less than about 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20% ofthe cross-sectional width of the inside surface 114 of the fluid barrel.Such designs in which the cross-sectional width of the interior surface124 of the retraction barrel is less than the cross-sectional width ofthe inside surface 114 of the fluid barrel, provides ergonomic andfunctional advantages. For example, the overall appearance and handlingof the dual barrel syringe is more appealing to the user. In certainembodiments, the retraction barrel can be nested within the fluidbarrel. For example, both the retraction barrel and the fluid barrel mayboth be bounded or circumscribed by a common wall, and the retractionbarrel may be partially or fully disposed within the fluid barrel, oralternatively, a dividing wall may separate a single barrel into twoseparate barrels, a fluid barrel and a retraction barrel.

The open distal end 121 of the retraction barrel 120 in the embodimentmay be fully open or partially enclosed by, for example, a barrier wall(not shown) that partially encloses the open distal end 121. The opendistal end 121 may be free of a barrier wall and may be fully open. Insuch embodiments, the needle hub assembly forms a closure around theopen distal end 121 such that there is fluid communication between theneedle cannula and the aperture 123 that permits fluid communicationbetween the fluid barrel 110 and the retraction barrel 120. In oneembodiment, as shown in FIG. 5, the wall 122 may include a secondaperture (not shown) that permits fluid communication with the fluidchamber 115 and the needle chamber 125. The second aperture of the wallmay also allow fluid communication between the fluid chamber 115, needlechamber 125 and the needle cannula. The fluid communication between thefluid barrel 110 and retraction barrel 120 may be provided by a firstconduit (not shown) that extends from a first aperture (not shown) ofthe fluid barrel 110 and the second aperture (not shown) of theretraction barrel.

Described another way, the retractable syringe assembly includes abarrel including an open proximal end 119, a sidewall 112 having aninside surface defining a fluid chamber 115 for retaining fluid andhaving a first cross-sectional width and a needle chamber 125 forhousing a needle hub assembly, the fluid chamber and the needle chamberbeing circumscribed by a common wall (sidewall 112) and divided intoseparate chambers (fluid chamber 125 and needle chamber 125) in fluidcommunication

According to one or more embodiments, the retraction barrel has across-sectional dimension that is smaller than the cross-sectionaldimension of the fluid barrel. In specific embodiments, the crosssectional dimension of the retraction barrel is less than about 90%,80%, 70%, 60%, 50%, 40%, 30%, or 20% of the cross-sectional dimension ofthe fluid barrel. Such designs in which the cross-sectional dimension ofthe retraction barrel is less than the cross-sectional dimension of thefluid barrel, provides ergonomic and functional advantages. For example,the overall appearance and handling of the dual barrel syringe is morepleasing to the user.

The needle hub assembly may include a second conduit (not shown) thatextends from an open end of the needle cannula to second aperture (notshown) of the retraction barrel. The second conduit may include anopening (not shown) that must be aligned with the second aperture topermit fluid communication between the needle cannula and the fluidbarrel.

The needle hub assembly 140 is disposed within the retraction barrel 120and includes a needle hub 142 and a needle cannula 150 attached to theneedle hub 142. The needle hub 142 includes a distal end 141 and aproximal end 149. The needle cannula 150 includes a free and open distalend 151 end and an open proximal end 159 that is attached to the distalend 141 of the needle hub. The needle hub 142, shown in FIGS. 4 and 8,includes a needle hub body 143 and a needle cannula support 146 disposeddistally within the needle hub body 143. The needle cannula support 146includes a recessed portion (not shown) for partially housing one end ofthe needle cannula. The recessed portion may include a portion of thesecond conduit (not shown) that extends through the needle hub 142 tothe second aperture (not shown) of the retraction barrel to permit fluidcommunication between the needle cannula 150 and the fluid barrel 110.

The needle cannula 150 of the needle hub assembly 140 is biased to movein the proximal direction. In the embodiment shown, the needle hubassembly 140 is biased to move in the proximal direction, therebybiasing the attached needle cannula 150. In the embodiment shown, theneedle hub assembly 140 is biased to move in the proximal direction by abiasing element 152 disposed between the needle hub body 143 and theneedle cannula support 148. As shown more fully in FIGS. 13-17, thebiasing element 152 is shown as surrounding the needle cannula support146. To assemble the needle hub assembly 140 with the biasing element152, the biasing element 152 is initially placed over the needle cannulasupport 146 and compressed, as shown in FIG. 13. The needle hub body 143includes a distal end 144, a proximal end 145, distal portion 147disposed adjacent to the distal end and proximal portion 148 disposedadjacent to the proximal end. The distal portion 147 may include aconical fitting with an opening (not shown) therethrough for receivingthe needle cannula 150. The proximal end 148 includes two hingedenclosing walls 155, 156. The enclosing walls 155, 156 surround theneedle cannula support and the biasing element 152 as they are assembledwith the needle hub body 143. Specifically, the needle cannula 150 isinserted into the opening of the distal portion 147 as shown in FIG. 14.The cross-sectional width of the opening increases from the proximal endof the distal portion 147 to the distal end of the distal portion 147 sothat the needle cannula 150 extends through the opening, while theneedle cannula support 146 remains within the distal portion 147. Thetwo hinged enclosing walls 155, 156 of FIGS. 15-16 are moved inwardlyuntil they surround the needle cannula support 146 and the biasingelement 152, as shown in FIG. 17.

In the embodiment shown, the biasing element 152 engages the needlecannula support 146. The biasing element 152 may include a spring, whichmay be a compression spring that applies a constant force on the needlehub body 143 in the proximal direction. In alternative embodiments, thebiasing element 152 may be provided in another form, for example, alever arm (not shown) may be disposed between the needle hub and thebarrier wall. The needle hub body 143 includes a frangible element 153that supports biasing element 152, the needle cannula support 146 andthe needle cannula 150 from moving in the proximal direction. As will beexplained in greater detail below, breaking the frangible element 153will allow the biased needle hub 142 and the needle cannula 150 attachedthereto to retract into the retraction barrel 120.

In one or more variants, the entire needle hub assembly 140 may bebiased. For example, the needle hub body 143, needle cannula support 146and the needle cannula 150 may be provided as an integral unit that isbiased and the retraction barrel may include a support element (notshown) that is frangible and applies a force on the needle hub assembly140 in the distal direction. The biasing element 152 may be locatedbetween the needle hub assembly 140 and the distal end 121 of theretraction barrel 120. The force applied by the support element to theneedle hub assembly 140 in the distal direction counteracts the forceapplied to the needle hub assembly 140 by the biasing element 152 in theproximal direction. Once the support element is broken, the needle hubassembly 140 may be retracted into the retraction barrel 120.

The frangible element 153 is shown in FIGS. 8-12 as a partiallyextending shelf wall 154 that is disposed along portions of the insidesurface of the needle hub body 143. The shelf wall 154 extends radiallyinwardly to form a supporting barrier that is positioned adjacent to thebiasing element 152 that surrounds the needle cannula support, whichprevents movement or expansion of the biasing element 152. Once thefrangible element 153 is broken, for example, by the movement of thetrigger element 190 in the distal direction, the engagement between thebiasing element 152 and the needle cannula support 146 cause the biasingelement 152 to move the needle cannula support 146 and the needlecannula 150 attached thereto into the trigger element 190 and/or theretraction barrel 120. Specifically, the expansion of the biasingelement 152 drives the needle cannula support 146 and the needle cannula150 into the trigger element 190 and/or the retraction barrel 120.

The needle hub assembly is sized moveable within the needle chamber. Thesize and shape of the needle hub assembly may be modified to permitmovement in needle chambers having different sizes. In the assembledstate, prior to use, the needle hub assembly is positioned at the opendistal end of the retraction barrel.

A plunger rod 160 is disposed within the fluid barrel 110 and includes astopper 170 attached thereto for forming a fluid-tight seal with theinside surface 114 of the fluid barrel 110. The plunger rod 160 mayinclude a reuse prevention feature that locks the plunger rod 160 withinthe fluid barrel 110 or otherwise disables the plunger rod 160. Theplunger rod may include a reuse prevention feature that cooperates witha reuse prevention feature disposed on the fluid barrel 110. In one ormore embodiments, the plunger rod may include a protrusion 113 that hasa cross-sectional width that is greater than the cross-sectional widthof the inside surface 114 of the fluid barrel 110 at the retainingelement (not shown). As discussed above, the retaining element forms asmaller cross-sectional width than at other locations along the lengthof the fluid barrel 110. Accordingly, when the protrusion of the plungerrod advances distally past the retaining element of the fluid barrel110, the smaller cross-sectional width of the retaining element preventsmovement of the protrusion in the proximal direction. Accordingly, theplunger rod 160 is locked within the fluid barrel 110 by the retainingelement. In one or more embodiments, the stopper 170 and/or the plungerrod 160 may have a structure to permit relative movement of the plungerrod 160 with respect to the stopper 170. For example, the stopper 170may have an interior recess that allows the distal end of the plungerrod 160 to move in the distal and proximal directions within theinterior recess, thus elongating and shortening the length of theplunger rod and the stopper. Exemplary plunger rods and stoppers whichpermit relative movement of the plunger rod with respect to the stopperare disclosed in U.S. patent application Ser. Nos. 12/137,732 (publishedas United States Patent Application Publication Number 20090048560) andSer. No. 12/262,836 (published as United States Patent ApplicationPublication Number 20090131869), each of these applications beingincorporated herein by reference in its entirety.

The stopper 170 may also include reuse prevention features that alsocooperates with reuse prevention features disposed on the fluid barrel110. For example, the stopper 160 may include a sealing portion (notshown) that has a cross-sectional width that is greater than thecross-sectional width of the inside surface 114 of the fluid barrel 110at the retaining element. In such embodiments, removal of the stopper170 is prevented because the smaller cross-sectional width of theretaining ring of the fluid barrel 110 prevents the stopper 170 frombeing removed. The plunger rod 160 and the stopper 170 may be joined bya frangible connection 172 that may cause the plunger rod 160 to becomedisconnected from the stopper 170, while the stopper 170 remains lockedwithin the fluid barrel 110 by the retaining element. Exemplary stopperswhich include a reuse prevention feature and plunger rods and stoppersjoined by a frangible connection are disclosed in U.S. application Ser.Nos. 12/137,732 and 12/262,836, referred to above.

The retractable syringe assembly 101 also includes a trigger element 190that includes a distal end 191 and a proximal end 199. The triggerelement 190 is moveable independently of the plunger rod 160 and extendsinto the needle chamber 125 of the retraction barrel 120. In theembodiment shown in FIG. 4, the trigger element 190 includes a triggerpad 194 on which the user applies a force in the distal direction toactivate the retraction mechanism of the syringe assembly.

The trigger element 190 is sized, shaped and positioned to provide atrigger force on the frangible element 153 of the needle hub body 143 torelease the biasing element 152 so the needle cannula 150 retracts andis housed into the retraction barrel. The trigger element 190 includes atrigger element body 192 that extends from the distal end 191 to theproximal end 199. The trigger element body 192 is shaped to have acylindrical shape and is elongate. In the embodiment shown, the triggerelement 190 has an open distal end 191 and the trigger element body 192has a hollow interior 193 to house the needle hub 142 and the needlecannula 150. The proximal end 199 of the trigger element is closed andmay be tapered to retain the needle hub 142 within the hollow interior193 after the needle hub 142 and the needle cannula 150 is retractedinto retraction barrel. The needle cannula support 146 may also includestructure to retain the retracted needle cannula support 146 and theneedle cannula 150 within the trigger element 190.

The open distal end 191 of the trigger element may have a beveled edgethat breaks the frangible element 153 more efficiently by concentratingthe force applied to the frangible element 153. The breaking of thefrangible element 153 releases the force applied to the biasing element152 and the needle cannula support 146 in the distal direction. Afterthe release of this distally direction force, the force applied on theneedle cannula support 146 by the biasing element 152 in the proximaldirection remains due to the compression of the biasing element 152. Theexpansion of the biasing element 152 or the presence of the proximallydirected force on the needle cannula support 146 by the biasing element152 causes the needle hub 142 to retract or move into the retractionbarrel 120 or specifically, the hollow interior 193 of the triggerelement.

In use, as shown in FIGS. 8-10, the user is free to aspirate fluid orliquid into the fluid barrel 110 and expel the fluid withoutinadvertently activating the retraction mechanism and retracting theneedle cannula. After the user aspirated and expelled the liquid asdesired, the user may activate the retraction mechanism by applying aforce on the trigger element 190 in the distal direction. The separateretraction barrel 120 and the needle chamber 125 allows the use of areliable or constant activation force to activate the retractionmechanism. Specifically, the activation force is no longer dependent onthe viscosity of the liquid filled within the fluid chamber 115. Inaddition, the activation force no longer has to compensate for the riskof accidental activation during normal operation of the syringeassembly, and, therefore, the activation force may be set at a lowlevel. Moreover, because the retraction feature no longer has to cutthrough a stopper, as required by some retractable syringe assemblies,the activation force can be optimized to solely activate the retractionfeature, instead of also being optimized to penetrate stoppers.

In addition, the separation of the retraction mechanism from the fluidbarrel 110 also reduces the risk of accidental activation because it isno longer coupled with the aspiration and injection of the fluid usingthe plunger rod. Accordingly, there is no risk of premature activationof the retraction mechanism by applying high force during high speedinjections. In use, after the finger or thumb is used to apply a forceon the plunger rod 160 to expel the contents of the fluid barrel 110,the user simply shifts the finger or thumb to the trigger pad 194disposed adjacent to the thumb press 164 at the proximal end of theretraction barrel 120. The user does not need to modify their grip orutilize two hands to activate the retraction mechanism, as is requiredin known embodiments of retractable syringe assemblies.

The separation of the retraction barrel, needle hub assemblies and theretraction feature of the syringe assemblies disclosed herein alsoallows the use of exchangeable needles for all dimensions of theretractable syringe. The asymmetrical orientation of the needle hubassembly, with respect to the entire syringe assembly, facilitates lowangle injections (i.e. subcutaneous injections). Further, theasymmetrical orientation also allows the user to detent needle cannulaorientation by simply gripping the syringe assembly.

In one or more embodiments, the needle hub assembly may be attached tothe retraction barrel to provide a leak proof pathway for the liquid. Inone or more embodiments, this is accomplished by utilizing a needle hubassembly that includes a sealing member, which is activated by thepressing and turning required to assemble the needle hub assembly. Thepressing and turning motions are achieved by incorporating slightlywedged surfaces on the needle hub assembly which attach to correspondingstructures on the retraction barrel. The needle hub assembly may also bedesigned to be turned and attached in one direction. This allows theneedle hub assembly to be locked in a defined position, while the torqueapplied is turned into sealing pressure.

In the embodiment shown in FIGS. 18-23, the needle hub assembly 200 maybe shaped and sized to cooperate with the retracting barrel 220 and aneedle shield 240 to provide sealing pressure to the retraction barrel.In the embodiment shown, the retraction barrel 220 includes a wall 223that extends from an open distal end 221. The wall includes a securingelement 222 disposed at the distal end 221 for securing the needle hubassembly 200 to the retraction barrel. The securing element 222 isformed integrally with the sidewall of the barrel, as shown in FIG. 18.In the embodiment shown, the securing element 222 includes at least oneindentation or opening 224 for receiving a corresponding finger elementor other protrusion on the needle hub assembly. In the embodiment shown,the opening 224 extends in a distal direction from the open distal end221. The securing element also includes at least one inwardly extendingprotuberance 226 that is disposed adjacent to the opening 224. Theprotuberance 226 extends inwardly into the open distal end 221 of theretraction barrel.

The retraction barrel 220 is attached to a fluid barrel 230 with a fluidchamber (not shown) that includes an aperture 232 for permitting fluidcommunication between the needle hub assembly 200 and the fluid chamber.The aperture 232 is disposed on the opposite side of the open distal end221 of the retraction barrel from the protuberance 226. The securingelement 222 of the retraction barrel may include alternative structurewhich cooperates with the needle hub assembly 200 to secure the needlehub assembly 200 to the retraction barrel.

As shown in FIG. 19, the needle hub assembly 200 is assembled with aneedle shield 240 prior to attachment to the retraction barrel. As shownin FIG. 23, the needle hub assembly includes a needle hub body 202having a distal end 203 and a proximal end (not shown). The distal end203 includes an opening 204. A needle cannula 205 is disposed within theneedle hub body 202 and extends through the opening 204 of the needlehub body. A biasing element (not shown) may be disposed within theneedle hub body 202 as otherwise described herein, for example, withreference to FIGS. 8-17. The needle hub body 202 includes an outsidesurface 206 that includes an attachment element 208 that engages thesecuring element 222 of the retraction barrel 220. The outside surface206 has a generally rounded conical shape or a curved conical shape. Inthe embodiment shown, the attachment element 208 of the needle hubassembly includes at least one radially outwardly extending tab 210disposed on the outside surface 206 of the needle hub body. The tab 210engages the protuberance 226 by sliding under the protuberance 226 suchthat the protuberance 226 exerts a force in the proximal direction onthe tab 210, when the needle hub assembly 200 is attached to theretraction barrel.

The needle hub body 202 also includes an open conduit 212 for permittingfluid communication between the needle cannula 205 and the aperture 232of the fluid barrel. In the embodiment shown, the position and locationof the attachment element 208 and the securing element 222 permitsalignment of the open conduit 212 and the aperture 232. Moreover, properengagement of the attachment element 208 and the securing element 222ensures fluid communication between the fluid barrel 230 and the needlecannula 205.

In the embodiment shown, the needle hub body 202 also includes at leastone finger element 214 disposed along the outside surface 206.Specifically, the finger element 214 has a distal end 215 that isattached to the outside surface 206 and proximal end 216 that is freeand unattached to the outside surface 206 of the needle hub body 202. Inthe embodiment shown in FIG. 23, the finger element 214 is flexible toextend outwardly from the outside surface of the hub body. Applicationof a radially outwardly-directed force on the finger elements 214 causethe proximal end 216 to lift off the outside surface 206 of the needlehub body. The finger element 214 in the embodiment shown has an elongateshape that extends a distal ring 217 that is disposed distally adjacentto the midpoint between the distal end 203 and the proximal end (notshown) of the needle hub body 202. The distal ring 217 in the embodimentshown forms an indentation on the outside surface 206 of the needle hubbody 202 that extends along the perimeter of the outside surface 206. Inone variant, the distal ring may form a rib that extends outwardly fromthe outside surface 206.

The finger element 214 has a rounded distal end 215 in the embodimentshown, but may include a distal end 215 having a different shape. Thefinger element 214 forms a raised platform with respect to the outsidesurface 206 of the needle hub body 202. From the distal end 215 to abent portion 218, the finger element 214 extends substantially parallelto the conically shaped outside surface 206 of the needle hub body 202.From the bent portion 218 to the proximal end 216, the finger element214 extends substantially parallel to the retraction barrel 220. Theoutside surface 206 also includes an indented portion 207 adjacent tothe finger element 214. The indented portion 207 does not have a curvedconical shape, like the remaining portions of the outside surface 206,but instead, has a surface that is parallel to the retraction barrel oris inwardly curved with respect to the retraction barrel. The fingerelement 214 and the indented portion 207 are disposed adjacent to thetab 210. In the embodiment shown, the needle hub body 202 includes twotabs 210 located across the needle hub body 202 from one another and theindented portion 207 and the finger element 214 disposed therebetween.The open conduit 212 is disposed on the opposite side of the tab 210from the finger element 214 and the indented portion 207.

The needle shield 240 is disposed over the needle hub body 202 such thatit encloses the needle cannula 205. The needle shield 240 providesprotection to the user from the needle cannula 205 and preventscontamination of the needle cannula 205. The needle shield 240 alsoactivates the engagement of the needle hub assembly 200 and the securingelement 222 of the retraction barrel. In the embodiment shown, theneedle shield 240 has structure that engages the needle hub body 202 andfacilitates the rotation thereof, with respect to the retraction barrel220 such that the needle hub assembly 200 is properly attached to theretraction barrel. In the embodiment shown, the needle shield 240includes a closed distal end (not shown), an open proximal end 249 and ahollow body 242 defining a cavity 243 for receiving the needle hub body202 and the needle cannula 205. The hollow body 242 includes an interiorsurface 242. The interior surface 242 includes the structure thatenables the needle shield 240 to engage the needle hub body 202 andfacilitate attachment of the needle hub assembly 200 to the retractionbarrel.

The interior surface 242 includes a plurality of detents 244 that extendinwardly and engage the at least one finger element 214 of the needlehub body 202. The detents 244 engage the finger element 214 to rotatethe needle hub body 202 with respect to the securing element 222 toattach the needle hub assembly 200 to the open distal end of theretraction barrel.

As shown in FIG. 20, as the needle hub assembly 200 and the needleshield 240 are placed within the open distal end 221 of the retractionbarrel, the finger element 214 flexes as it moves over the wall 223 ofthe retraction barrel. As the user rotates the needle shield 240 andneedle hub assembly 200 attached thereto, the detents 244 engage thefinger element 214 and apply a rotational force on the finger element214 to rotate the needle hub body 202 and needle hub assembly 200 untilthe tab 210 engages the protuberance 226 of the retraction barrel andthe finger element 214 engages the opening 224 of the wall 223 of theretraction barrel. Upon engagement of the tab 210 and protuberance 226and the finger element 214 and the opening 224, the aperture 232 isaligned with the open conduit 212 of the needle hub assembly. In otherwords, the engagement of the securing element 222 and the attachmentelement 208 permits fluid communication between the aperture and theneedle cannula. After proper engagement of the securing element 222 andthe attachment element 208, the needle shield may be removed from theneedle hub body 202.

To remove the needle hub assembly 200 from the retraction barrel, theuser places the needle shield 240 over the needle hub body 202 and theneedle cannula 205 and applies a rotational force to the needle shield240, which in turn causes the detents 244 to apply a rotational force onthe finger element 214 and cause the needle hub body 202 to rotate inthe opposite direction to disengage that tab 210 from the protuberance226 and the finger element 214 from the opening.

A second aspect of the present invention pertains to a retractablesyringe assembly that provides for the separate containment of theretraction mechanism and the needle cannula in a needle chamber. Theassembly also includes an activation button, located at the proximal endof the syringe assembly, that extends within the needle chamber and islocated adjacent to the plunger rod used to aspirate and expel fluidfrom a separate fluid chamber disposed adjacent to the needle chamber.On activation of the button, the needle hub is released into the needlechamber.

The embodiments according to the second aspect provide an alternativemechanism to a retractable needle syringe. Typical retractable needlesyringes provide a chamber within the plunger rod to house the needlecannula and other associated components after the retraction mechanismis activated. This requires increased component complexity to enable thesealed plunger and stopper to be breached during activation. The dualbarrel design of the embodiments according to the second aspect movesthe retraction mechanism into a dedicated region allowing a conventionalplunger and stopper to be used.

Most conventionally designed retractable needles (single barrel designswith plunger activated retraction) are activated after dosing by acontinued pressure on the rear of the plunger rod. As these are the sameforces that must be applied during dispensing of the medication,inadvertent activation can occur. Specifically, such devices may beinadvertently activated during dosing if sufficient pressure isgenerated, i.e., during the expulsion of a viscous medication from thebarrel, which requires higher forces to be applied and such forces mayexceed the forces needed to activate the retraction mechanism. In otherknown devices, the pressure generated at the stopper may be sufficientto cause failure of the stopper or any removable opening into theplunger rod.

The retraction mechanisms of conventional type, plunger-activated safetysyringes must withstand increased syringe pressures and the associatedlarge plunger forces as described above. This leads to a requirement forlarge activation forces which exceed the operational forces by somesafety margin in order to prevent premature retraction. Additionally,since most devices of this type employ an additional plunger motionafter full dispensing, and in the same direction as the dispensingmotion, a threshold force must be employed to allow the user todifferentiate between a fully bottomed plunger and the activationoperation.

By incorporating a separate release mechanism, distinct from the plungerrod, this limitation is removed in the dual barrel design, and therelease activation force can be arbitrarily specified based on userrequirements, ergonomics and safety considerations. Further, decouplingthe retraction activation from the plunger rod allows for a separate anddistinct control to be utilized for the needle retraction affording theoperator greater control over when needle retraction occurs and removingthe possibility of inadvertent actuation. Moreover, since the plungerrod and the stopper are no longer utilized with the retractionmechanism, existing plunger rods and stoppers from existing devices maybe utilized with embodiments described herein.

A retractable syringe assembly 300 according to one or more embodimentsof the second aspect is shown in FIGS. 24-29. The syringe assembly 300includes a dual syringe barrel that includes fluid barrel 310 and aretraction barrel 320. The retractable syringe also includes a needlehub assembly 340, a plunger rod 360, stopper 370 and a trigger element390. The fluid barrel shown in FIGS. 27A-D includes a distal end 311, aopen proximal end 319, a sidewall 312 extending from the distal end 311and the proximal end 319 including an inside surface 314 defining achamber 315. The inside surface 314 defines a cross-sectional width andmay include a reuse prevention feature, that will be discussed ingreater detail below. The distal end 311 includes a distal wall 317 thatencloses the distal end 311. In the embodiment shown, the sidewall 312includes a first aperture 330 for permitting fluid communication betweenthe fluid barrel and the retraction barrel. As will be discussed ingreater detail below, the first aperture 330 also permits fluidcommunication between a needle cannula disposed within the retractionbarrel 320 and the fluid barrel 310.

The fluid barrels shown in FIGS. 24-29 may include a reuse preventionfeature. Specifically, the fluid barrel 310 may include a retainingelement 309 that extends around the entire circumference of the insidesurface 314 of the fluid barrel 310 at a location adjacent to theproximal end 319 of the fluid barrel. The cross-sectional width of theinside surface 314 at the retaining element is less than the firstcross-sectional width or the cross-sectional width of the inside surface314 at the remaining locations along the length of the fluid barrel. Inone or more embodiments, optional tabs or detents can be used to createa region of the fluid barrel 310 having a cross-sectional width that isless than the first cross-sectional width of the fluid barrel 310. Theretaining element may also be shaped to facilitate activation of thereuse prevention feature. For example, the fluid barrel 310 may alsoinclude a diameter transition region disposed proximally adjacent to theretaining element at the proximal end 319 of the fluid barrel 310. Thecross-sectional width of the inside surface 314 of the fluid barrel atthe diameter transition region increases from the distal end 311 to theproximal end 319 of the fluid barrel 310. As will be described ingreater detail below, in embodiments of the retractable syringe assemblythat utilize a reuse prevention feature, the reuse prevention feature ofthe fluid barrel 310 cooperates with corresponding reuse preventionfeatures on the plunger rod 360 to lock the plunger rod 360 within thefluid barrel 310 and/or to disable the plunger rod 360 from further use.

As more clearly shown in FIGS. 27A-D, the retraction barrel 320 isdisposed adjacent to the sidewall 312 of the fluid barrel 310. Theretraction barrel 320 is configured to house a needle hub assembly 340therein and the retraction feature. The retraction barrel 320 includesdistal end 321 and an open proximal end 329. The distal end includes atapered wall segment 232 that houses the needle hub assembly 340therein. A wall 322 having an interior surface 324 defining the needlechamber 325 extends from the open distal end 321 to the open proximalend 329. The wall 322 of the retraction chamber is adjacent to thesidewall 312 of the fluid barrel 310. In one or more embodiments, thewall 322 may extend around the portions of the retraction barrel 320that are not in direct contact with fluid barrel 310 and the sidewall312 may form the barrier between the retraction barrel 320 and the fluidbarrel 310. In other words, the outside surface of the sidewall 312 mayform the interior surface 324 of the retraction barrel 320 along theportion of the retraction barrel 320 that is in direct contact with thefluid barrel 310.

The size of the needle chamber 325 may be modified to accommodate theneedle hub assembly 340 and/or the retraction feature. According to oneor more embodiments, the interior surface 324 of the retraction barrel320 has a cross-sectional width that is smaller than the firstcross-sectional width of the fluid barrel 310. In specific embodiments,the cross-sectional width of the interior surface 324 of the retractionbarrel is less than about 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20% ofthe cross-sectional width of the inside surface 314 of the fluid barrel.Such designs in which the cross-sectional width of the interior surface324 of the retraction barrel is less than the cross-sectional width ofthe inside surface 314 of the fluid barrel, provides ergonomic andfunctional advantages. For example, the overall appearance and handlingof the dual barrel syringe is more appealing to the user. In certainembodiments, the retraction barrel can be nested within the fluidbarrel. For example, both the retraction barrel and the fluid barrel mayboth be bounded or circumscribed by a common wall, and the retractionbarrel may be partially or fully disposed within the fluid barrel, oralternatively, a dividing wall may separate a single barrel into twoseparate barrels, a fluid barrel and a retraction barrel.

The wall 322 may include a second aperture 332 that permits fluidcommunication with the fluid chamber 315 and the needle chamber 325. Thesecond aperture of the wall may also allow fluid communication betweenthe fluid chamber 315, needle chamber 325 and the needle cannula.

According to one or more embodiments, the retraction barrel across-sectional dimension that is smaller than the cross-sectionaldimension of the fluid barrel. In specific embodiments, the crosssectional dimension of the retraction barrel is less than about 90%,80%, 70%, 60%, 50%, 40%, 30%, or 20% of the cross-sectional dimension ofthe fluid barrel. Such designs in which the cross-sectional dimension ofthe retraction barrel is less than the cross-sectional dimension of thefluid barrel, provides ergonomic and functional advantages. For example,the overall appearance and handling of the dual barrel syringe is morepleasing to the user

The needle hub assembly may include a fluid path 354 that extends froman open end of the needle cannula to second aperture 332 of theretraction barrel. The second conduit may include an opening (not shown)that must be aligned with the second aperture to permit fluidcommunication between the needle cannula and the fluid barrel.

Referring to FIGS. 28 and 28A, the needle hub assembly 340 disposedwithin the retraction barrel 320 and includes a needle hub 342 and aneedle cannula 350 attached to the needle hub 342. The needle hub 342includes a distal end 341 and a proximal end 349. The needle cannula 350includes a free and open distal end 351 end and an open proximal end 359that is attached to the distal end 341 of the needle hub. The needle hub342 shown in FIGS. 28 and 28A includes a recessed portion 355 forpartially housing one end of the needle cannula. The recessed portion355 is in fluid communication with the fluid path 354 to permit fluidcommunication between the needle cannula 350 and the fluid barrel 310.

The needle cannula 350 of the needle hub assembly 340 is biased to movein the proximal direction. In the embodiment shown, the needle hubassembly 340 is biased to move in the proximal direction, therebybiasing the attached needle cannula 350. The needle hub assembly 340 isbiased to move in the proximal direction by a biasing element 352disposed between the needle cannula 350 and the tapered wall segment 323of the retraction barrel. As shown more fully in FIGS. 26-27, thebiasing element 352 is shown as surrounding the needle cannula 350.

In the embodiment shown, the biasing element 352 engages the needlecannula 350. The biasing element 352 may include a spring, which may bea compression spring that applies a constant force on the needle hub 342in the proximal direction. In alternative embodiments, the biasingelement 352 may be provided in another form, for example, a lever arm(not shown) may be disposed between the needle hub and the barrier wall.The needle hub 342 includes at least one hub seal 343 disposed along theoutside surface of the needle hub 342 for forming a fluid tight sealwith the tapered wall segment 323 of the retraction barrel. As will bedescribed in greater detail below, the trigger element 390 supports theneedle hub 342 and prevents biasing element 352 from moving in theproximal direction. The needle hub 342 includes at least one detent 344that receives and engages the corresponding structure on the triggerelement 390 that supports the needle hub 342. As will be explained ingreater detail below, disengaging the detent 344 from the correspondingstructure on the trigger element will allow the biased needle hub 342and the needle cannula 350 attached thereto to retract into theretraction barrel 320.

In the embodiment shown, for example in FIGS. 25, 28 and 28A, the needlehub 342 includes a first attachment portion. In the embodiment shown,the first attachment portion is provided in the form of at least twodetents 344 or grooves 345 disposed on opposite ends of the needle hub342. The grooves 345 are disposed adjacent to the proximal end 349 ofthe needle hub assembly. The grooves are shown as including a firstportion inclined radially inwardly into the needle hub 342, a secondportion that has no incline and is substantially parallel to the axisalong which the needle hub is disposed, and a third portion thatinclines sharply radially outwardly. The first attachment portionfacilitates engagement of the trigger element 390 with the grooves 345.The third portion 347 prevents disengagement of the trigger element 390until a sufficient force is applied to the trigger element 390.Specifically, the sharp incline of the third portion 347 prevents thetrigger element from sliding over and out of the detent 344, whenengaged with the detent 344. Once a sufficient force is applied to thetrigger rod 390 to overcome the third portion 347 of the detent 344,referred herein as the trigger force, the disengagement of the triggerelement 390 from the needle hub 342 permits the biasing element 352 tomove the needle cannula 350 and the needle hub 342 attached thereto intothe trigger element 390 and/or the retraction barrel 320. Specifically,the expansion of the biasing element 352 drives the needle cannula 350and the needle hub 342 into the trigger element 390 and/or theretraction barrel 320.

The needle hub assembly is sized moveable within the needle chamber. Thesize and shape of the needle hub assembly may be modified to permitmovement in needle chambers having different sizes. In the assembledstate, prior to use, the needle hub assembly is positioned at the opendistal end of the retraction barrel.

A plunger rod 360 is disposed within the fluid barrel 310 and includes astopper 370 attached thereto for forming a fluid-tight seal with theinside surface 314 of the fluid barrel 310. The plunger rod 360 mayinclude a reuse prevention feature that locks the plunger rod 360 withinthe fluid barrel 310 or otherwise disables the plunger rod 360. Theplunger rod may include a reuse prevention feature that cooperates witha reuse prevention feature disposed on the fluid barrel 310. In one ormore embodiments, the plunger rod may include a protrusion 313 that hasa cross-sectional width that is greater than the cross-sectional widthof the inside surface 314 of the fluid barrel 310 at the retainingelement (not shown). As discussed above, the retaining element form asmaller cross-sectional width than at other locations along the lengthof the fluid barrel 310. Accordingly, when the protrusion of the plungerrod advances distally past the retaining element of the fluid barrel310, the smaller cross-sectional width of the retaining element preventsmovement of the protrusion in the proximal direction. Accordingly, theplunger rod 360 is locked within the fluid barrel 310 by the retainingelement. In one or more embodiments, the stopper 370 and/or the plungerrod 360 may have a structure to permit relative movement of the plungerrod 360 with respect to the stopper 370. For example, the stopper 370may have an interior recess that allows the distal end of the plungerrod 360 to move in the distal and proximal directions within theinterior recess, thus elongating and shortening the length of theplunger rod and the stopper. Exemplary plunger rods and stoppers whichpermit relative movement of the plunger rod with respect to the stopperare disclosed in U.S. application Ser. Nos. 12/137,732 and 12/262,836referred to above and are incorporated herein by reference.

The stopper 370 may also include reuse prevention features that alsocooperates with reuse prevention features disposed on the fluid barrel310. For example, the stopper 370 may include a sealing portion (notshown) that has a cross-sectional width that is greater than thecross-sectional width of the inside surface 314 of the fluid barrel 310at the retaining element. In such embodiments, removal of the stopper370 is prevented because the smaller cross-sectional width of theretaining element of the fluid barrel 310 prevents the stopper 370 frombeing removed. The plunger rod 360 and the stopper 370 may be joined bya frangible connection 372 that may cause the plunger rod 360 to becomedisconnected from the stopper 370, while the stopper 370 remains lockedwithin the fluid barrel 310 by the retaining ring. Exemplary stopperswhich include a reuse prevention feature and plunger rods and stoppersjoined by a frangible connection are disclosed in U.S. application Ser.Nos. 12/137,732 and 12/262,836 and are incorporated herein by reference.

The retractable syringe assembly 300 also includes a trigger element 390that includes a distal end 391 and a proximal end 399. The triggerelement 390 is moveable independently of the plunger rod 360 and extendsinto the needle chamber 325 of the retraction barrel 320. In theembodiment shown, the trigger element 390 includes a trigger pad 394 onwhich the user applies a force in the distal direction to activate theretraction mechanism of the syringe assembly.

The trigger element 390 includes a trigger element body 392 that extendsfrom the distal end 391 to the proximal end 399. The trigger elementbody 392 is shaped to have a cylindrical shape and is elongate. In theembodiment shown, the trigger element 390 has an open distal end 391 andthe trigger element body 392 has a hollow interior 393 to house theneedle hub 342 and the needle cannula 350. The proximal end 399 of thetrigger element is closed and may be tapered to retain the needle hub342 within the hollow interior 393 after the needle hub 342 and theneedle cannula 350 is retracted into retraction barrel. The needlecannula 350 may also include structure to retain the retracted needlecannula 350 within the trigger element 390.

The distal end 391 of the trigger element 390 includes a secondattachment portion 394 for engaging the first attachment portion. In theembodiment shown, the second attachment portion includes at least oneflexible arm 395 that extends distally from the trigger element body393. The flexible arm 395 includes a release member 396 that is shaped,sized and positioned to engage the grooves 345 of the needle hub 342.Specifically, the detent includes a first segment 346 that is inclinedradially inwardly, a second portion that has no incline and issubstantially parallel to the axis along which the trigger element 390is disposed, and a third segment 347 that inclines sharply radiallyoutwardly. It will be understood that the release member 396 may haveanother shape or size that does not replicate the shape and size of thegrooves 345.

The interior surface 324 of the retraction barrel may include a capturerib 380 for capturing or retaining the flexible arm 395 of the triggerelement 390 upon application of the trigger force. Specifically, thecapture rib 380 is disposed adjacent to the tapered wall segment 323 andextends into the needle chamber 325. The capture rib has a distal endthat is attached to the interior surface of the retraction barrel and afree proximal end that extends into the needle chamber 325. The capturerib 380 is contoured to facilitate the distal end 391 of the triggerelement 390 to slide over or ride over the capture rib 380 uponapplication of a trigger force that permits the release member 396 todisengage from the grooves 345 and the trigger rod moves in the distaldirection. As shown more clearly in FIG. 26, as the flexible arm 395 ofthe trigger element 390 slides over the capture rib 380, the flexiblearm 395 flexes or moves outwardly. The capture rib 380 holds theflexible arm 395 in the flexed position and permits the needle hub 342,the needle cannula 350 and the biasing element 352 to move proximallypast the release member 396 into the hollow interior 393 of the triggerelement.

The retraction barrel 320 includes a release opening 383 disposedadjacent to the proximal end of the retraction barrel. The releaseopening 383 may be enclosed to form an indentation in the wall 322 ofthe retraction barrel. The trigger element 390 includes a release detent397 disposed on the trigger element body 392 that engages the releaseopening 383. The release opening 383 and the release detent 397 providean indication to the user for how much force is sufficient to overcomethe grooves 345 of the needle hub 342. This indication can be a visualindication, a tactile indication, or a combination of visual and tactileindication. Specifically, the force required to disengage the releasedetent 397 from the release opening 383 is the same or substantially thesame as the trigger force. The height of the release detent 397 may bemodified to require more or less force to disengage the release detent397 from the release opening 383. In addition, the release opening 383may be modified to have curved entrances to decrease the angle betweenthe interior surface of the wall 322 and the release opening 383. Inembodiments where the release opening 383 is open and not enclosed, therelease opening 383 and the release detent 397 provide visual indicationwhether the trigger force has been applied. Specifically, the user cansee whether the release detent 397 is engaged with the release opening383 and know whether the trigger force has been applied.

In one or more embodiments, the trigger force, which is the forcerequired to disengage the release detent 397 from the release opening383 and/or to disengage the release member 396 from the groove 345 is atleast about 4 pounds of force (lbf). In one or more variants, thetrigger force is about 4 lbf. In another variant, the trigger force mayinclude 2 lbf, 3 lbf, 4 lbf, 5 lbf, or 6 lbf. In a more specificembodiment, the trigger force is in the range from about 3.5 lbf toabout 4.5 lbf.

In the embodiment shown, the needle hub assembly is permanently attachedto the retraction barrel 320 because it is enclosed within theretraction barrel. In one or more alternative embodiments, the needlehub assembly may be removably attached to the retraction barrel 320 ormay be attached by the user to the open distal end 321 of the retractionbarrel.

Referring to FIG. 29, the length of the plunger rod 360, the triggerelement 390 and the syringe barrel 301 may be modified so that theplunger rod 360 aligns with the trigger element upon expulsion of all ofthe contents of the syringe, as shown in FIG. 29. The alignment of theplunger rod 360 and the trigger element 390 provides one or more ofvisual indication and tactile indication that the contents of the fluidbarrel 310 have been expelled and the needle cannula 350 can beretracted into the retraction barrel. Further, such alignment of thetrigger element 390 and the plunger rod 360 after the stopper 370 is incontact with the distal wall 317 of the fluid barrel 310 requires thatthe trigger element 390 is not aligned with the plunger rod 360 when thefluid barrel is filled. Specifically, the trigger element 390 is locatedcloser to the proximal end 329 of the retraction barrel and the proximalend 319 of the fluid barrel than the plunger rod 360. This alignment,when retraction of the needle cannula is not desired, reduces the chanceof inadvertent activation of the retraction mechanism.

A third aspect of the present invention pertains to a retractablesyringe assembly that incorporates structure to prevent prematureactivation of the retraction mechanism. The retractable syringe assemblyis shown in FIGS. 30-32. In the embodiments shown in FIGS. 30 and 32,the syringe assembly 400 includes a dual syringe barrel as otherwisedescribed herein that includes a retraction barrel 420 and a fluidbarrel 410. A trigger element 490 is disposed within the retractionbarrel 420 and a plunger rod 460 is disposed within the fluid barrel410. The plunger rod 460 and the trigger element 490 have features thatprevent the plunger rod from interacting with the trigger element 490and accidentally activating the trigger element 490. In addition, theplunger rod 460 and the trigger element 490 have reuse preventionfeatures that prevent the user from reusing the syringe assembly 400.These premature activation prevention features and reuse preventionfeatures of the trigger element 490 and the plunger rod 460 describedwith respect to the third aspect may be incorporated with other triggerelements and plunger rods described herein.

The trigger element 490 includes a distal end (not shown) and a proximalend 499 and a trigger element body 492 that extends from the distal endto the proximal end 499. A snap 494 is disposed adjacent to the proximalend 499. In the embodiment shown, the snap 494 is located between thetrigger element 490 and the plunger rod 460. The snap 494 engages theretraction barrel and the engagement therebetween hinders or preventsmovement of the trigger element 490 in the distal direction. As shown inFIG. 30, the snap 494 is shown as a radially outward extension thatextends from the trigger element body 492. The snap 494 includes adistal end 495 and a proximal end 496. The snap 494 has a height thatincreases from the proximal end 496 to the distal end 495 to permit orfacilitate movement of the plunger rod 460 past the snap 494. The distalend 495 of the snap 494 is shown as substantially perpendicular to thetrigger element body

The snap element 494 is depressible upon application of a force in thedistal direction. The snap element 494 is not depressible uponapplication of a force in the proximal direction. Accordingly, theengagement of the snap element 494 with the retraction barrel 420applies a force on the snap element 494 in the proximal direction, whichprevents the snap element from depressing and hinders movement of thetrigger element 490 in the distal direction. When the plunger rod 460 ismoved in the distal direction, it depresses the snap element 494 andpermits movement of the trigger element 490 in the distal direction. Theplunger rod 460 may include a contacting surface, shown in FIGS. 30-32as a flat radial ring 462, that deflects the snap element 494 so thetrigger element 494 may be moved in the distal direction and theactivation of the retraction mechanism can proceed.

In use, as shown in FIGS. 31-32, the movement of the plunger rod in thedistal direction to expel all the contents of the fluid barrel 410depresses the snap element 494. When the plunger rod is bottomed or whenall the contents of the fluid barrel 410 are expelled and the stopper isin contact with the distal end of the fluid barrel, the plunger rodcontinues to depress the snap element 494. The depression of the snapelement 494 permits movement of the trigger element 490 only after thecontents of the syringe are expelled. Accordingly, premature activationof the retraction mechanism is prevented.

The underlying principle of the snap element 494 is that the inclusionof an abrupt angled surface, which can be as much as 90 degrees),engages the retraction barrel and prevents distal movement of thetrigger element. The snap element 494 may have sufficient stiffness inthe axial direction but may be easily deflectable in the radialdirection. This ensures smooth deflection when the plunger rod engagesthe snap element 494.

In one or more embodiments, the snap element 494 may be rotatable so itmay be to be turned away during transport and storage, as shown in FIGS.58-60. Prior to use or prior to activation, as shown in FIG. 58, thetrigger element 490 may be turned or rotated such that the snap element494 is positioned to prevent movement of the trigger element 490 in thedistal direction, as shown in FIG. 59. Thereafter, when activation ofthe retraction mechanism is desired, for example, when the contents ofthe fluid barrel 410 has been expelled, the trigger element 490 may berotated such that the snap element 494 is positioned to permit movementof the trigger element 490 in the distal direction, as shown in FIG. 60.

The trigger element 490 and the retraction barrel 420 include a reuseprevention feature. The retraction barrel 420 includes a first lockingelement 440 disposed adjacent to its proximal end which engages with asecond locking element 450 disposed on the trigger element body 492. Thefirst locking element 440 is shown as an opening 442 on the wall 422 ofthe retraction barrel 420. It will be understood that the opening may beprovided in other forms. The second locking element 450 is shown as anoutwardly extending projection 452 disposed on the trigger element body492. The projection 452 has a proximally facing stop face 454 thatprevents movement of the trigger element 492 in the proximal directionand prevents disengagement of the first locking element 440 and thesecond locking element 450.

The first locking element and the second locking element 450 arepositioned on the retraction barrel 420 and the trigger element 490 sothey can engage when a force is applied to the trigger rod in the distaldirection to activate the retraction mechanism. As shown in FIG. 32,upon application of the force on the trigger element 490 in the distaldirection, the projection 452 engages the opening 442.

A reuse prevention feature of the trigger element may be designed to beeasily deflectable in the radial direction when the trigger elementcontacts the interior surface of the retraction barrel 420. In the finalposition of the first and second locking elements 440, 450, theprojection 452 of the trigger element 490 should reach the opening 442where the projection 452 can re-expand and lock backward motion of thetrigger element 490. This will prevent the trigger element 490 frombeing pulled out of the retraction barrel 420 and activated for multipleactivations of the retraction mechanism. By adding this reuse feature tothe device, the retraction mechanism can only be activated once, thuspreventing re-use after for example exchanging the retracting needle.

A fourth aspect of the present invention pertains to a retractablesyringe assembly 500 that includes an alternative retraction mechanism.The retractable syringe assembly 500 is shown in FIGS. 33-37. Thesyringe assembly 500 includes a dual chamber syringe barrel as otherwisedescribed herein that includes a needle chamber and a fluid chamber. Aneedle hub assembly 540 according to the needle hub assembly describedwith reference to FIGS. 8-17, wherein a needle hub 542 encloses a needlecannula support 546, a needle cannula 550 that is attached to the needlecannula support and a biasing element 552 disposed between the needlecannula support 546, needle cannula 550 and the needle hub 542. Theneedle hub 542, as shown in FIGS. 33-37, include a distal end 553 and aproximal end 554. The distal end 553 may include a body portion 545having a conical shape and including an opening (not shown) therethroughfor receiving the needle cannula 550. The proximal end 554 includes afirst retraction portion 555 that extends in the proximal direction fromthe body 545 and defines a hub cavity for housing the needle cannulasupport 546, biasing element 552 and the needle cannula, as describedabove with reference to FIGS. 8-17. The first retraction portion 554includes a distal end 557 attached to the body portion 545 and a freeproximal end 556. The first retraction portion 555 also includes atleast one flexible portion 558 having an engaging tab 559 at theproximal end thereof. The engaging tab 559 engages the needle cannulasupport 546 and exerts a force on the needle cannula support 546 in thedistal direction to counteract the force applied by the biasing element552 in the proximal direction on the needle hub assembly 540.

The trigger element 590 includes a distal end 591 and a proximal end(not shown). The trigger element 590 also includes a trigger elementbody 592 extending from the distal end 591 to the proximal end, asotherwise described herein, which may include a hollow interior 593 forhousing the retracted needle cannula. The trigger element body 592includes a rib 594 that extends radially outwardly for disengaging theengaging tab 559 from the needle cannula support 546 and releasing theforce applied by the engaging tab 559 on the needle hub assembly 540.The trigger element 590 disengages the tab 559 and the needle cannulasupport 546 upon application of the trigger force by the triggerelement, which provides sufficient force in the distal direction on theengaging tab 559 and/or the flexible portion 558 to cause the flexibleportion 558 to move outwardly so the engaging tab 559 is no longerengaged with the needle cannula support 546 and the force applied by thebiasing element is no longer counteracted. Specifically, the removal ofthe force applied by the engaging tab 559 on the needle cannula support546 in the distal direction allows the force applied by the biasingelement 552 to move the needle cannula support 546 and needle cannula550 into the trigger element.

The embodiments described herein may include alternative retractionmechanisms that are disclosed in U.S. Provisional Application ReferenceNumber P-8842, U.S. provisional application Ser. No. 61/366,749,incorporated by reference in its entirety. Specifically, the retractionmechanisms disclosed in FIGS. 7-11, 18-22 and 24-27 of U.S. ProvisionalApplication Reference Number P-8842.

Alternative embodiments of the trigger element are shown in FIGS. 38-57,57A, 57B and FIGS. 61-66, which may be utilized with the syringeassemblies described herein.

In FIGS. 38, 38A, 38B, 39, 39A, 39B and 54, 54A, 54B and 55, theproximal end of the trigger element has a circular trigger pad thatsubstantially envelopes or surrounds the plunger rod in the openproximal end of the fluid barrel. The trigger element may be coded byindicia such as one or more of indentations, markings or color coding.Upon activation of the trigger element by applying a distal force on theplunger rod, the plunger rod proximal end or thumbpress may be fullynested within the trigger pad.

FIGS. 40-42 show a design in which the plunger rod engages the triggerelement shaped a semicircular element or crescent-shaped element. Theplunger rod thumbpress can be depressed to its distal most position, andthe user can then activate the trigger element by application of forceto the trigger element.

FIGS. 43-47 show a design in which proximal end of the trigger elementhas a substantially rectangular shaped trigger pad with curved edges andthe plunger rod can nest within the trigger pad. In FIGS. 48-50, thetrigger pad is substantially oval in shape. In FIGS. 51-53, the triggerpad is aligned with the needle cannula on one side of the finger flangeof the syringe assembly. In FIGS. 56, 57, 57A and 57B, the triggerelement has a trigger pad that is aligned with the needle cannula andneedle chamber, and the trigger pad extends outwardly from the body ofthe needle chamber. FIG. 61 shows a configuration in which the triggerelement is a small tab at the end of the needle chamber. FIG. 62 shows atrigger element as a tab that can be activated by applying a force inthe distal direction. The trigger element has a gripping surface in theform of a plurality of spaced ribs. FIG. 63 shows an alternative triggerelement design in which the trigger element is in the form of ablock-shaped that can be activated by the user. FIG. 64 shows a buttonembedded in the proximal end of the needle barrel that can be activatedby the user by pressing or squeezing the button to cause the needle toretract.

FIG. 65 shows a plunger rod thumbpress that has hinged portion that canbe moved by applying distal force to the hinged portion to activate thetrigger element an retraction mechanism. FIG. 66 shows a trigger elementthat is somewhat similar to FIG. 64, except that the trigger element isin the form of a toggle type element that can be radially moved toactivate the retraction mechanism.

In another embodiment of the present invention, a method for aspiratingand expelling a liquid from a syringe assembly of the present inventionis provided comprising aligning the trigger guard to prevent movement ofthe trigger element in the distal direction. A pre-selected amount ofliquid is then aspirated into the fluid chamber by inserting the needlecannula into the liquid and applying a force on the plunger rod in aproximal direction. The liquid from the fluid chamber is expelled byapplying a force on the plunger rod in the distal direction. The needlecannula is retracted into the retraction barrel by aligning the triggerguard to permit movement of the trigger element in the distal directionand applying a force on the trigger guard in the distal direction toprovide the trigger force causing the needle cannula to retract into theretraction barrel.

In another embodiment of the present invention, a method for aspiratingand expelling a liquid from a syringe assembly of the present inventionis provided comprising aspirating a pre-selected amount of liquid intothe fluid chamber by inserting the needle cannula into the liquid andapplying a force on the plunger rod in a proximal direction. The liquidfrom the fluid chamber is then expelled by applying a force on theplunger rod in the distal direction. The plunger rod is locked withinthe fluid barrel by applying a continuous force on the plunger rod inthe distal direction causing the protrusion of the plunger rod to movedistally past the retaining ring of the fluid barrel. The needle cannulais retracted into the retraction barrel by aligning the trigger guard topermit movement of the trigger element in the distal direction andapplying a force on the trigger guard in the distal direction to providethe trigger force causing the needle cannula to retract into theretraction barrel.

In another embodiment of the present invention, a method for aspiratingand expelling a liquid from a syringe assembly of the present inventionis provided comprising providing a syringe barrel including a fluidbarrel and a retraction barrel in fluid communication, the fluid barrelincluding a plunger rod attached to a stopper for aspirating andexpelling liquid from the fluid barrel and a retraction barrel includinga needle hub, needle cannula with an opening and a trigger element forproviding a trigger force causing the needle cannula to retract into theretraction barrel. The opening of the needle cannula is submerged in aliquid and the fluid barrel of the syringe is filled with the liquid byapplying a force to the plunger rod in a proximal direction. The liquidfrom the fluid barrel is expelled by applying a force to the plunger rodin a distal direction. The needle cannula is then retracted into theretraction barrel by applying a force to the trigger element in thedistal direction to provide the trigger force.

In another embodiment of the present invention, a method for aspiratingand expelling a liquid from a syringe assembly of the present inventionis provided further comprising locking the plunger rod in the fluidbarrel after expelling the liquid from the fluid barrel.

In another embodiment of the present invention, a method for aspiratingand expelling a liquid from a syringe assembly of the present inventionis provided wherein the force applied to the plunger rod is orientedalong an axis that is parallel to the axis along which the force appliedto the trigger element is oriented.

In another embodiment of the present invention, a method for aspiratingand expelling a liquid from a syringe assembly of the present inventionwherein the force applied to the plunger rod to expel the liquid is lessthan the force applied to the trigger element.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe invention. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the invention.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present invention without departing from the spirit andscope of the invention. Thus, it is intended that the present inventioninclude modifications and variations that are within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A syringe assembly comprising: a fluid barrelincluding a sidewall having an inside surface defining a fluid chamberfor retaining fluid and having a first cross-sectional width, an openproximal end and a distal end including a distal wall; a plunger roddisposed within the fluid chamber comprising a distal end, a proximalend, a plunger rod body extending from the distal end to the proximalend, and a stopper disposed at the distal end of the plunger rod forforming a fluid-tight seal with the inside surface of the barrel; aretraction barrel disposed adjacent to the sidewall of the fluid barrel,the retraction barrel including a wall having an interior surfacedefining a needle chamber, an open proximal end, an open distal endincluding a barrier wall, an aperture between the wall of the retractionbarrel and the sidewall of the fluid barrel permitting fluidcommunication between the fluid chamber and the needle chamber and aneedle hub assembly comprising a needle hub, a needle cannula attachedto the needle hub, the needle cannula being in fluid communication withthe aperture and biased to move in a proximal direction; a biasingelement disposed between the needle cannula and the wall of theretraction barrel; and a trigger element disposed within the needlechamber and moveable within the retraction barrel independently from theplunger rod, the trigger element providing a trigger force causing theneedle cannula to retract into the retraction barrel.
 2. The syringeassembly of claim 1, wherein the needle hub assembly is disposed at theopen distal end of the retraction barrel, the needle hub assemblyfurther comprising a first attachment portion, the trigger elementincluding a second attachment portion for engaging the first attachmentportion.
 3. The syringe assembly of claim 2, wherein the needle hubassembly is removably attached to the retraction barrel.
 4. The syringeassembly of claim 2, wherein the needle hub assembly is permanentlyattached to the retraction barrel.
 5. The syringe assembly of claim 2,wherein the trigger force disengages the second attachment portion fromthe first attachment portion so the needle cannula is retracted withinthe retraction barrel.
 6. The syringe assembly of claim 5, wherein theneedle cannula is biased by a spring disposed between the needle hub andthe retraction barrel that exerts a force on the needle cannula in aproximal direction.
 7. The syringe assembly of claim 6, wherein theretraction barrel includes a tapered distal end and the spring isdisposed between the needle hub and the tapered distal end of theretraction barrel.
 8. The syringe assembly of claim 5, wherein theinside surface of the fluid chamber sidewall includes a retaining ringadjacent to the proximal end defining a second cross-sectional widththat is less than the first cross-sectional width and the plunger rodbody includes a flexible protrusion having a cross-sectional widthgreater than the cross-sectional width of the barrel at the rib and afrangible portion.
 9. The syringe assembly of claim 8, wherein thecontact between the stopper and the distal wall of the barrel causes theprotrusion to advance distally past the rib in the barrel and lock theplunger rod in the barrel to prevent reuse of the syringe assembly. 10.The syringe assembly of claim 9, wherein continuous application of aforce on the plunger rod in the proximal direction after the protrusionhas advanced distally past the rib causes the frangible portion tobreak.
 11. The syringe assembly of claim 8, wherein the distal end ofthe plunger rod includes a stopper-engaging portion and the stopper isattached to the stopper-engaging portion of the plunger rod, the stopperbeing distally and proximally movable relative to the stopper- engagingportion for a pre-selected axial distance such that when a force isapplied to the plunger rod in the distal direction and the distal end ofthe stopper is in contact with the distal wall of the barrel, theprotrusion is permitted to advance distally past the rib in the barreland lock the plunger rod in the barrel to prevent reuse of the syringeassembly.
 12. The syringe assembly of claim 11, wherein continuousapplication of a force on the plunger rod in the proximal directionafter the protrusion has advanced distally past the rib causes thefrangible portion to break.
 13. The syringe assembly of claim 5, whereinthe first attachment portion comprises a groove disposed on at least aportion of an outside surface of the needle hub and the secondattachment element comprises at least one flexible arm extendingdistally from the distal end of the trigger element, the flexible armincluding at least one locking member that extends inwardly for engagingthe groove disposed on the needle hub.
 14. The syringe assembly of claim13, wherein the trigger element includes a free proximal end, a free andopen distal end that provides the trigger force, and a trigger elementbody extending from the proximal end to the distal end and including aninterior surface defining a hollow interior.
 15. The syringe assembly ofclaim 14, wherein the needle cannula is retracted into the retractionbarrel and housed within the hollow interior of the trigger element. 16.The syringe assembly of claim 14, wall of the retraction barrel includesa release opening and the trigger element body includes a release detentdisposed adjacent to distal end of the trigger element that engages theopening of the retraction barrel.
 17. The syringe assembly of claim 16,wherein the trigger force includes application of a force on the triggerelement in the distal direction that is sufficient to disengage therelease detent of the trigger element from the release opening in thewall of the retraction barrel.
 18. The syringe assembly of claim 17,wherein the trigger force is at least 4 lbf.
 19. The syringe assembly ofclaim 17, wherein the retraction barrel includes a rib that extendsproximally from the barrier wall for retaining the flexible arm uponapplication of the trigger force.
 20. The syringe assembly of claim 19,wherein the trigger force is about 4 lbf.
 21. The syringe assembly ofclaim 19, wherein, upon application of the trigger force, the flexiblearm is moved in a proximal direction to disengage the locking memberfrom the groove of the needle hub and slides over the rib to permit theneedle cannula to retract into the retraction barrel.
 22. The syringeassembly of claim 21, wherein, prior to the application of the triggerforce, the proximal end of the trigger element is aligned with theproximal end of the plunger rod.
 23. The syringe assembly of claim 22,wherein after the application of the trigger force, the proximal end ofthe trigger element is no longer aligned with the proximal end of theplunger rod.
 24. The syringe assembly of claim 22, wherein the alignmentof the trigger element and the plunger rod provides visual indication ofthe retraction of the needle cannula.